Mate, you'll eventually learn this is (the majority of the time) a no win situation, unless you have a bit of arsehole in you. It goes a little something like this 85% of the time:
Honest way #1
Man: Hey, I'm not really looking for a relationship. I genuinely like you though. Can we keep things casual.
Woman: No, looking for a little more substance in my life. I'm after commitment.
Honest way #2 (occurs majority of time, be weary of it)
Man: Hey, I'm not really looking for a relationship. I genuinely like you though. Can we keep things casual.
Woman: Hey, sure. I'm not after anything serious at all either.
Man: Great.
....6 weeks later.
Woman: So, where is this headed? What are we exactly?
Man: .........

Wtf? I thought it was casual, woman?
Woman: It is, but what are we?
Man's options at this point: Get the fuck out, quickly. Or continue.
....2 years later.
Woman: So, Amanda got engaged last week. So what about us? Am I ever going to get married?
Man:
.....4 years later.
Woman: So, Amanda just had her first kid. She's so cute. I'm thinking we should start trying too. You know, just so they can have play dates.
Man:
The end.